The present invention relates to a method and apparatus for supporting a graft assembly during the repair of an abdominal aortic aneurysm using a novel support device to prevent migration of the graft assembly within the abdominal aorta.
An aneurysm is a ballooning of the wall of an artery resulting from the weakening of the artery due to disease or other conditions. Left untreated, the aneurysm will frequently rupture, resulting in loss of blood through the rupture and death.
Aortic aneurysms are the most common form of arterial aneurysm and are life threatening. The aorta is the main artery which supplies blood to the circulatory system. The aorta arises from the left ventricle of the heart, passes upward and bends over behind the heart, and passes down through the thorax and abdomen. Among other arterial vessels branching off the aorta along its path, the abdominal aorta supplies two side vessels to the kidneys, the renal arteries. Below the level of the renal arteries, the abdominal aorta continues to about the level of the fourth lumbar vertebrae (or the navel), where it divides into the iliac arteries. The iliac arteries, in turn, supply blood to the lower extremities and perineal region.
It is common for an aortic aneurysm to occur in that portion of the abdominal aorta between the renal arteries and the iliac arteries. This portion of the abdominal aorta is particularly susceptible to weakening, resulting in an aortic aneurysm. Such an aneurysm is often located near the iliac arteries. An aortic aneurysm larger than about 5 cm in diameter in this section of the aorta is ominous. Left untreated, the aneurysm may rupture, resulting in rapid, and usually fatal, hemorrhaging. Typically, a surgical procedure is not performed on aneurysms smaller than 5 cm as no statistical benefit exists to do so.
Aneurysms in the abdominal aorta are associated with a particularly high mortality rate; accordingly, current medical standards call for urgent operative repair. Abdominal surgery, however, results in substantial stress to the body. Although the mortality rate for an aortic aneurysm is extremely high, there is also considerable mortality and morbidity associated with open surgical intervention to repair an aortic aneurysm. This intervention involves penetrating the abdominal wall to the location of the aneurysm to reinforce or replace the diseased section of the abdominal wall (i.e., abdominal aorta). A prosthetic device, typically a synthetic tube graft, is used for this purpose. The graft serves to exclude the aneurysm from the circulatory system, thus relieving pressure and stress on the weakened section of the aorta at the aneurysm.
Repair of an aortic aneurysm by surgical means is a major operative procedure. Substantial morbidity accompanies the procedure, resulting in a protracted recovery period. Further, the procedure entails a substantial risk of mortality. While surgical intervention may be indicated and the surgery carries attendant risk, certain patients may not be able to tolerate the stress of intra-abdominal surgery. It is, therefore, desirable to reduce the mortality and morbidity associated with intra-abdominal surgical intervention.
In recent years, methods have been developed to attempt to treat an abdominal aortic aneurysm without the attendant risks of intra-abdominal surgical intervention. Although techniques have been developed that may reduce the stress, morbidity, and risk of mortality associated with surgical intervention to repair aortic aneurysms, none of the prior art systems that have been developed effectively treat the aneurysm and exclude the affected section of aorta from the pressures and stresses associated with circulation. None of the devices disclosed in the references provide a reliable and quick means to reinforce an aneurysmal artery. In addition, all of the prior references require a sufficiently large section of healthy aorta abutting the aneurysm to ensure attachment of the graft. The proximal aortic neck (i.e., above the aneurysm) is usually sufficient to support a graft""s attachment means. However, when an aneurysm is located near the iliac arteries, there may be an ill-defined neck or no neck below the aneurysm. Such an ill-defined neck would have an insufficient amount of healthy aortic tissue to which to successfully attach a graft. Furthermore, much of the abdominal aortic wall may be calcified making it extremely difficult to attach a graft thereto.
There are a number of shortcomings with the presently available graft products and their fixation within the abdominal aorta. Although sizing of xe2x80x9ctubexe2x80x9d or xe2x80x9cbifurcatedxe2x80x9d grafts is radiographically assessed prior to surgery, it is necessary for the surgeon to have a large selection of graft lengths and diameters on hand to ensure an appropriate surgical outcome. Additional shortcomings include the placement of a xe2x80x9ccircularxe2x80x9d profile graft with an associated fixation device within an essentially xe2x80x9covoidxe2x80x9d profiled vessel and the use of attachment means which fasten only to the insubstantial, structurally compromised (diseased) intima and media layers (i.e., strata) of the vessel wall. Research has shown yet another problem which indicates that the necks of the post-surgical aorta increase in size for approximately twelve months, regardless of whether the aneurysm experiences dimensional change. This phenomenon can result in perigraft leaks and graft migration.
Graft migration is a significant problem affecting many of the grafts available within the intraluminal abdominal aortic aneurysm market. These grafts are attached within the aortic lumen at a proximal positioning by means of stents, which provide outward radial forces thereby forcing the graft into the lumen wall. In some instances barbs, part of the stent fabrication, provide additional fixation. There are numerous problems with this design approach. The stent of the aforementioned concept is expanded into a compromised vessel having questionable mechanical integrity. Second, the proximal distal neck has been shown to expand immediately post operatively and for a period of twelve months thereafter causing the graft to detach from or loosen with respect to the lumen. Finally, the barbs of the stent product are of questionable merit as they fasten into the intima of the lumen wall which has compromised mechanical integrity.
By comparison, the present inventors developed a graft assembly disclosed in U.S. patent application Ser. No. 08/896,415, filed Jul. 18, 1997, entitled xe2x80x9cMethod and Apparatus for the Surgical Repair of Aneurysms,xe2x80x9d the disclosure of which is incorporated herein by reference, that is positively fastened to the adventia, the outermost of three strata within the vessel wall, having appropriate mechanical integrity. The grafts disclosed in U.S. patent application Ser. No. 08/896,415 are not comprised by expansion of the distal neck. The present invention addresses the short comings of the prior art grafts. The present invention also enhances the performance of the graft assembly disclosed in U.S. patent application Ser. No. 08/896,415.
It is therefore an object of the present invention to overcome the above-identified shortcomings of the prior art.
It is another object of the present invention to provide a support device for a graft assembly.
It is another object of the present invention to provide a support device for a graft assembly to support the graft assembly within a vessel.
It is another object of the present invention to provide a support device for a graft assembly that supports the graft assembly to prevent graft migration in a cephalad/caudad direction within the vessel.
It is another object of the present invention to provide a support device for a graft assembly to provide additional securement points for securing the graft assembly to the vessel wall.
It is another object of the present invention to provide a support device for a graft assembly to reduce the impact of vessel expansion on the graft assembly when located within the vessel.
It is another object of the present invention to provide a support device for a graft assembly within a vessel without impeding blood flow arteriorly (towards the intestine).
It is another object of the present invention to provide a support device for a graft assembly within a vessel without impeding blood flow posteriorly (towards the spine).
It is another object of the present invention to provide a support device for a graft assembly having at least one attachment assembly that is capable of being secured within the thoracic or suprarenal aorta.
It is another object of the present invention to provide a support device for a graft assembly that does not block blood flow to and from the renal arteries.
It is another object of the present invention to provide a support device for a graft assembly formed from a biocompatible material.
It is another object of the present invention to provide a support device for a graft assembly having at least one attachment assembly to prevent graft migration in a cephalad/caudad direction.
It is another object of the present invention to provide a graft repair system for use in the surgical repair of aneurysms within a vessel.
It is another object of the present invention to provide a graft repair system having a graft assembly and a support assembly to prevent migration of the graft assembly within a vessel.
The prevent invention is directed to a support device for supporting a graft assembly within a vessel. The graft assembly includes a tubular portion having a proximal end. The support device in accordance with the present invention includes at least one attachment assembly for attaching the graft assembly to a vessel wall of the vessel. The at least one attachment assembly is capable of being secured to the vessel wall. The support device further includes a connecting assembly for connecting the attachment assembly to the proximal end of the graft assembly, such that the attachment assembly extends from the proximal end of the graft assembly. The support device further includes a securing assembly for securing the connecting assembly to the proximal end of the graft assembly.
In accordance with the present invention, the at least one attachment assembly may include at least one attachment pad. Alternatively, the at least one attachment assembly may include an attachment tube or collar. The at least one attachment assembly may be formed from a biocompatible material such as, Gore-Tex(copyright).
In accordance with the present invention, the connecting assembly may include a support assembly that extends from the at least one attachment assembly to the proximal end of the graft assembly. The support assembly may include at least one support leg that extends from the attachment assembly to the proximal end of the graft assembly.
In accordance with the present invention, the attachment assembly may include a plurality of attachment assemblies. The at least one support leg extends to each of the plurality of attachment assemblies.
The present invention is also directed to a graft repair system for use in the repair of aneurysm within a vessel. The graft repair system includes a graft assembly and a support device for supporting the graft assembly within the vessel. The graft assembly may include a tubular portion, a proximal end and a distal end. The graft assembly may be a bifurcated graft assembly. The graft assembly may further comprise a flexible attachment assembly extending from the distal end of the graft assembly. The support device in accordance with the present invention includes at least one attachment assembly for attaching the graft assembly to a wall of the vessel. The at least one attachment assembly is capable of being secured to the vessel wall. The support device further includes a connecting assembly for connecting the attachment assembly to the proximal end of the graft assembly, such that the attachment assembly extends from the proximal end of the graft assembly. The support device further includes a securing assembly for securing the connecting assembly to the proximal end of the graft assembly.